Flexible composite cure fixture

Details Flexible composite cure fixture Flexible composite cure fixture

1998-09-01

2001-10-09

Copenheaver, Blaine (Department: 1772)

Stock material or miscellaneous articles

Structurally defined web or sheet

Including sheet or component perpendicular to plane of web...

C425S403000, C425S468000, C249S155000, C249S156000, C249S175000

Reexamination Certificate

active

06299964

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to resin composite cure fixtures, and more particularly to fixture having a mandrel which may be alternatively positioned for fabricating resin composite beams having a variety of configurations and sizes.
BACKGROUND OF THE INVENTION
The use of composite material in commercial and military applications is well known. Composite materials are desirable due to their mechanical characteristics such as a high strength to weight ratio and high thermal tolerances. As such, composite materials are used to build structural supports such as beam members.
Various applications such as rockets, launch vehicles, airliners and other vehicles generally characterized by large cylindrical sections, require large structural internal supports. Typically, the cylindrical sections are comprised of an outer skin supported by internal supports which take the form of circular shaped beams. Additionally, circular shaped beams may be used to join multiple cylindrical sections by providing a common internal support to which the outer skins of two cylinders may be attached.
Design requirements for a given launch vehicle type, for example, may provide for cylindrical sections having a generally similar outer skin diameter. Thus, the underlying internal structural supports or beams for various launch vehicles may have roughly the same outer moldline. Due to various considerations (such as loading and weigh), however, the beams are often required to have different cross-sectional configurations and dimensions associated with particular launch vehicles. Thus, generically fabricated beams are typically feasible and specialized tooling is often utilized to make the various beams.
It is therefore evident that there exists a need in the art for tooling for fabricating beams which is flexible so as to facilitate the production of beams having a variety of cross-sectional configurations and dimensions.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a composite forming/curing fixture for fabricating beam members defined by a beam axis of radial symmetry. Each beam member has a web, at least one outer flange extending from the web and a first web inner radius formed between the web and the outer flange. The fixture is used for forming and curing beam members having a variety of cross-sectional configurations with variable web sizes, flange sizes and first web inner radii.
The fixture is provided with a mandrel defined by a mandrel axis of radial symmetry which is co-located with the beam axis of radial symmetry. The mandrel axis is perpendicular to a mandrel plane. The mandrel is disposable in first and second positions with respect to the mandrel plane. The mandrel has opposing first and second mandrel surfaces orthogonal to the mandrel axis of radial symmetry, an annular third mandrel surface extending about the mandrel axis of radial symmetry, a first edge interposed between the first and third mandrel surfaces and defined by a first edge radius and a second edge interposed between the second and third mandrel surfaces defined by a second edge radius. The first mandrel surface is disposed adjacent the mandrel plane while the mandrel is in the first position and the second mandrel surface is disposed adjacent the mandrel plane while the mandrel is in the second position.
The fixture is further provided with a back plate having annular first and second surfaces defined by a back plate axis of radial symmetry which is co-located with the beam axis of radial symmetry. The first and second surfaces are disposable about opposing sides of the mandrel plane. The fixture is further provided with a web forming space for forming the web of the beam member therein. The web forming space is respectively adjacent the first mandrel surface while the mandrel is disposed in the first position and is respectively adjacent the second mandrel surface while the mandrel is disposed in the second position. The fixture is further provided with a first web inner radius forming space for forming the first web inner radius of the beam member therein. The first web inner radius forming space is respectively adjacent the first edge while the mandrel is disposed in the first position and respectively is adjacent the second edge while the mandrel is disposed in the second position. The fixture is further provided with a first outer flange forming space for forming the outer flange therein. The first outer flange forming space is interposed between the third surface of the mandrel and the first surface of the back plate. The fixture is further provided with a second outer flange forming space for forming the outer flange therein. The second outer flange forming space is adjacent to and concentrically within the second surface of the back plate.
The fixture of the present invention is contemplated to be used for forming curved resin composite beam structures. In practice, resin sheets which may be fiber reinforced are applied to the various fixture surfaces. For example, when forming the web of a beam member, the resin sheets are consecutively laid upon the first mandrel surface within the web forming space until a desired web thickness is obtained. Additional resin sheets may be consecutively positioned adjacent the third mandrel surface to a desired thickness. The resin is allowed to cure within the fixture by heating and vacuum-bagged the resin thereon.
In the preferred embodiment of the present invention, the fixture is provided with a base plate formed to support the mandrel and back plate in vacuum-tight engagement thereon. Additionally, a back plate slip sheet may be inserted concentrically between the mandrel and the back plate. In this respect, the outer flange of the beam member is formed between the back plate slip sheet and the mandrel. Similarly, an outer mandrel slip sheet may be inserted concentrically between the mandrel and the back plate. The outer flange of the beam member is formed between the outer mandrel slip sheet and the mandrel.
Further, the mandrel may be formed to have an annular forth mandrel surface and the beam member may be formed to have a first inner flange which is formed adjacent the forth mandrel surface. The fixture may further be provided with an inner mandrel slip sheet which is inserted concentrically within the mandrel adjacent the forth mandrel surface for forming the inner flange thereon.
Additionally, the beam member may be provided with a second inner flange and the fixture may be provided with an annular insert plate for forming the second inner flange thereon. The insert plate has an outer surface which is disposable on an opposing side of the mandrel plane with respect to the mandrel.
As such, based on the foregoing, the present invention mitigates the inefficiencies and limitations associated with prior art fixture. The fixture of the present invention facilitates flexibility of the beam members fabricated. In this respect, beam members may be formed to have a variety of web thicknesses, widths and radii. Advantageously, the fixture of the present invention is contemplated to facilitate the fabrication of beam members having various cross-sectional configurations as provided by the addition of various flanges to a common web. By adding flanges to a common web, a variety of cross-sectional shapes may be readily formed and include those which are, for example, L-shaped, Z-shaped, C-shaped, T-shaped, J-shaped and H- or I-shaped.
Such flexibility is accomplished while utilizing a common mandrel and back plate, which are the largest and heaviest fixture components. In particular, the mandrel is capable of being flipped over or rotated to reveal alternate moldline characteristics. Thus, unlike prior art tooling, the fixture of the present application does not require a specialized mandrel or back plate to be constructed to facilitate the part design flexibility as described above. Flexibility is further enhanced via the usage of the various slip sheets and inserts. The slip sheets and inserts readily ac

Affiliated with

Also associated with

Rating

Flexible composite cure fixture does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Flexible composite cure fixture, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flexible composite cure fixture will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2596805